Hello...

Now, i create the file management system to our company. But i face some problem that is i dont know how to check whether this file is already open by other people or not. Becasue each file just can access by one user, if other user want to access the same file,
it might be blocked by system.

So, what can i do? wait for your reply as soon as possible.
Thanks..

Read about flock() => http://php.net/manual/en/function.flock.php